Limitations of Multi-GNSS Positioning of USV in Area with High Harbour Infrastructure

Abstract

Satellite surveying techniques are currently among the main measuring technologies in geodesy and the main technologies in navigation. Modern navigation requires high accuracy of position coordinate determination, particularly in bathymetric surveys and aerial photogrammetry. In most cases, the terrain conditions enable positioning with high accuracy and reliability. These particularly involve the terrain conditions, i.e., high harbour infrastructure for bathymetric surveys and trees for railway surveys that hinder the measurement performance with a pre-determined accuracy. This article presents the limitations in unmanned survey vehicle (USV) positioning in an area restricted by a high quay, and difficult observational conditions in the surrounding high harbour infrastructure. The positioning used a four-system receiver that determined position coordinates based on the signals from one, two, three and four satellite navigation systems. The number of available satellites was determined under conditions of the open upper hemisphere and the partially obscured hemisphere based on the surrounding geometry. The determined position coordinates were related to the position determined using robotic total station (RTS). An area was identified in which it becomes difficult or impossible to maintain the required positioning accuracy.